Knee Confidence Is Related To Corticospinal Excitability In Patients 4-6 Months Post-Anterior Cruciate Ligament Reconstruction

PURPOSE: Psychological factors, primarily measured via the Anterior Cruciate Ligament-Return to Sport after Injury Survey (ACL-RSI) and Tampa scale of Kinesiophobia-11 (TSK-11), have become common components of clinical assessment in determining risk for reinjury and readiness to return to participation or sport following anterior cruciate ligament reconstruction (ACLR). Emerging evidence in this area is beginning to investigate the relationship between cortical physiology and reported measures of psychological factors. However, the relationship between corticospinal excitability (CSE) and psychological readiness has not been studied. The purpose of this study was to determine the relationship between psychological readiness (and its individual constructs) and CSE in patients after ACLR. We hypothesized there will be a positive relationship between ACL-RSI and CSE with greater readiness being associated with higher CSE. METHODS: Twenty participants (9 male) 4-6 months post ACLR underwent CSE (slope of a stimulus response curve, Slope) measures using an isokinetic dynamometer and transcranial magnetic stimulation. All participants completed the ACL-RSI and TSK-11 at time of testing. Univariate linear regressions were performed for each measure of CSE (AMT and Slope) with each of the ACL-RSI constructs (Emotions, Confidence, Risk-Appraisal), total ACL-RSI score, and total TSK-11 score. RESULTS: There was a positive relationship between the Slope and Confidence (p = 0.049, R2 = 0.199). No other associations were remarkable or reached statistical significance (Emotions-Slope p = 0.417, R2 = 0.037; Risk Appraisal-Slope p = 0.071, R2 = 0.170; ACL-RSI-Slope p = 0.139, R2 = 0.117; TSK-11-Slope p = 0.869, R2 = 0.002). CONCLUSIONS: Those with higher Slopes (greater CSE) reported greater knee confidence. Clinicians should consider the effects of knee confidence on CSE, given the established relationship between CSE and peak quadriceps torque. This work was funded by the National Center for Neuromodulation for Rehabiliation, an NIH Medical Rehabilitation Research Resource Network at the Medical University of South Carolina.